显示键盘时获取当前文本字段

Question

I want to get the current text field being edited when the keyboard was show. I need this to determine some y values for a frame animation. However, my keyboardWasShown method is running in the controller, so I can easily get the view but am uncertain how to get the correct text field. I have two text fields on this view.

//Move view to match keyboard when shown
-(void)keyboardWasShown:(NSNotification*)aNotification{

    //Get frame of keyboard
    NSValue* keyboardEndFrameValue = [[aNotification userInfo] objectForKey: UIKeyboardFrameEndUserInfoKey];
    CGRect keyboardEndFrame = [keyboardEndFrameValue CGRectValue];

    //Get animation properties of keyboard
    NSNumber* animationDurationNumber = [[aNotification userInfo] objectForKey:UIKeyboardAnimationDurationUserInfoKey];
    NSTimeInterval animationDuration = [animationDurationNumber intValue];
    NSNumber* animationCurveNumber = [[aNotification userInfo] objectForKey:UIKeyboardAnimationCurveUserInfoKey];
    UIViewAnimationCurve animationCurve = [animationCurveNumber intValue];
    UIViewAnimationOptions animationOptions = animationCurve << 16;

    //Set up animation
    [UIView animateWithDuration:animationDuration delay:0.0 options:animationOptions animations:^{
            CGRect viewFrame = self.view.frame;
            viewFrame.origin.y -= keyboardEndFrame.origin.y;
//I need the access to the text field here to determine y value.
            self.view.frame = viewFrame;
     } completion:^(BOOL finished){}];
}

Answer 1

use the Delegates of your UITextField and implement your

- (void)textFieldDidBeginEditing:(UITextField *)textField;

create an UITextField variable UITextField *flagTextField;

- (void)textFieldDidBeginEditing:(UITextField *)textField{
     flagTextField = textField;
}

Now you have the instance of textfield